A Sample of Charge Accounts at a Local Drug Store

Essay

A sample of charge accounts at a local drug store revealed the following frequency distribution of unpaid balances. $$\begin{array} { l c } \text { Unpaid Balance } & \text { Frequency } \\10 - 29 & 1 \\30 - 49 & 6 \\50 - 69 & 9 \\70 - 89 & 11 \\90 - 109 & 13\end{array}$$ ​
a.
Determine the mean unpaid balance.
b.
Determine the variance.
c.
Determine the standard deviation.
d.
Compute the coefficient of variation.